Zataria multiflora leaf powder in broiler diets: Effects on growth performance and meat quality traits

This study evaluated the effects of graded dietary levels of Zataria multiflora leaf powder (ZMLP) on growth performance and meat quality in broiler chickens. A total of 240 one-day-old male Ross 308 broiler chicks were assigned to four dietary treatments in a completely randomized design, with six replicate pens of 10 birds per treatment. Diets contained 0, 1, 2, or 3 g ZMLP/kg and were fed for 42 d. Over the entire experimental period, ZMLP supplementation increased body weight gain and reduced feed conversion ratio (P < 0.05), whereas feed intake was unaffected (P > 0.05). Dietary ZMLP decreased L* value and increased water-holding capacity in breast and thigh muscles and reduced cholesterol concentration in thigh muscle (P < 0.05). Muscle pH, a* and b* values, and breast muscle cholesterol concentration were unaffected (P > 0.05). Increasing ZMLP inclusion reduced total aerobic mesophilic bacterial and coliform counts and increased lactic acid bacterial count in both muscles (P < 0.05). ZMLP supplementation also increased total superoxide dismutase activity and total antioxidant capacity and decreased malondialdehyde concentration in both muscles (P < 0.05), whereas glutathione peroxidase activity remained unchanged (P > 0.05). Increasing dietary ZMLP decreased the proportion of saturated fatty acids and increased the proportion of polyunsaturated fatty acids in both muscles, while the proportion of monounsaturated fatty acids increased only in thigh muscle (P < 0.05). In conclusion, dietary ZMLP improved cumulative growth performance and favorably affected selected physicochemical, microbial, antioxidant, and fatty acid characteristics of broiler meat. Among the inclusion levels evaluated, 3 g ZMLP/kg produced the most consistent overall response.